Glycera Sheikhmujibi N. Sp.(Annelida: Polychaeta: Glyceridae): a New

diversity

Article Glycera sheikhmujibi n. sp. (Annelida: Polychaeta: Glyceridae): A New Species of Glyceridae from the Saltmarsh of Bangladesh

M. Belal Hossain 1,2,* and Pat Hutchings 3,4 1 Department of Fisheries and Marine Science, Noakhali Science and Technology University, Sonapur 3814, Noakhali, Bangladesh 2 Research Cell, Noakhali Science and Technology University, Sonapur 3814, Noakhali, Bangladesh 3 Australian Museum Research Institute, Australian Museum, 1 William Street, NSW 2010, Australia; [email protected] 4 Department of Biological Sciences, Macquarie University, North Ryde 2109, Australia * Correspondence: [email protected]

http://zoobank.org/urn:lsid:zoobank.org:pub:C2CEE260-5B4E-43B7-9251-2A0AB37EAB59 Received: 8 May 2020; Accepted: 24 May 2020; Published: 26 May 2020 Abstract: A new species of glycerid polychaete, Glycera sheikhmujibi, is described from the saltmarsh on the central coast of Bangladesh. The species is identiﬁed based on morphological characteristics using both a light microscope and scanning electron microscope (SEM). The species is characterized by the presence of three distinct types of proboscideal papillae: type 1 papillae (conical with three transverse ridges), type 2 (conical with a straight, median, longitudinal ridge), and type 3 (round, shorter, and broader, with a straight, median, longitudinal ridge). It has a Y-shaped aileron with gently incised triangular base, almost equal-size digitiform noto- and neuropodial lobes in the mid-body, and long ventral cirri at the posterior end. The new species is compared with its related species, previously described from the Bay of Bengal region. A key to all these species is provided.

Keywords: polychaete; Glyceridae; saltmarsh; new species; Bangladesh

1. Introduction The family Glyceridae currently has 87 accepted species (80 species of Glycera, one species of Glycerella, and ﬁve species of Hemipodus) (World Register of Marine Species, WoRMS; www.marinespecies.org). Among the three genera, Glycera and Glycerella possess biramous parapodia, whereas Hemipodus includes species with only uniramous parapodia throughout the body [1]. The ailerons, accessory supports on the proboscis, are rod-like in Glycerella, and mostly triangular-shaped or a more complicated structure having outer and inner rami in Glycera. Both Glycera and Hemipodus have spinigerous compound chaetae, but in Glycerella, additional compound falcigers are present [1]. Böggemann [2] revised all species of Glycera previously described worldwide and synonymised many of the previously described species (166), accepting only 36 as valid species. This was based on morphological data only, but subsequently he has used molecular studies to support some of these widely distributed species [3,4]. They are easily distinguishable from other polychaetes, as they have a pointed prostomium and eversible axial proboscis with numerous papillae. Glycera are widely distributed from tropical to temperate regions, and from intertidal to abyssal depths, inhabiting mainly soft bottom (sand/mud) sediments [1,3,5,6]. Glycerids are generally considered to be carnivorous burrowers, capturing and killing prey with their strong, well-developed jaws connected to venom glands that supply venom [7,8]. Polychaetes have been poorly studied in Bangladesh. While some benthic ecological studies have been carried out in the area [9–11], these studies have provided no taxonomic details, apart from the

Diversity 2020, 12, 213; doi:10.3390/d12060213 www.mdpi.com/journal/diversity Diversity 2020, 12, 213 2 of 15 listing of polychaete species and their abundance data. None of these studies have deposited any material, so the validity of these species cannot be confirmed. Pramanik et al. [12] reported a new record of Glyceridae, Glycera lancadivae Schmarda, 1861 [13], which seems to be similar to Glycera brevicirris Grube, 1870 [14] (known from Sri Lanka and the Andaman Sea). Of the 80 accepted species of Glycera Lamarck, 1818 [15], only 10 species have been recorded from the Bay of Bengal region (WoRMS; www.marinespecies.org). This region includes Bangladesh, India, Myanmar, Sri Lanka, and the tip of Andaman Nicobar Islands. Only one of these 10 species has been recorded from Bangladesh [12], in the northeastern corner of the Bay of Bengal: G. lancadivae Schmarda, 1861 [13]. Muir and Hossain [16] reported an unidentifiable glycerid fragment from the Halishahar Coast of Bangladesh, and they also provided taxonomic keys for identifying 14 species from the Bay of Bengal and Indo-Pacific regions. Subsequently, Hossain and Hutchings [17] emphasized the possibility of undescribed polychaete taxa from Bangladeshi coastal waters. Hence, the aim of this report is to describe a new species of Glycera from the Bangladesh Coast, and to provide an updated key to all species of Glycera recorded from the Bay of Bengal region.

2. Materials and Methods

2.1. Study Site Description The study area is located in an upper tidal channel of the lower Meghna river estuary, the largest estuarine ecosystem of Bangladesh, characterized by sunny tropical weather with monsoonal influence [18,19]. Mean annual temperature and rainfall in the study area are 25.5 ◦C and 2980 mm, respectively. According to the Köppen–Geiger climate classification, this climate is considered to be Am (tropical monsoon climate). The monsoon is characterized by strong southeastern winds with high rainfall, humidity, cloud cover, thunderstorms, cyclones, and occasional storm surges [18,19]. Almost all year round, the area is influenced by the incoming tide from Bay of Bengal. Tides are of a semi-diurnal type, with two high and two low waters during a lunar day. The tide varies with respect to magnitude, ranging from 0.07 m during neap tide to 4.42 m during spring tide [20]. The wave height of the estuary varies from 0 to 4 m [21]. However, the tidal wave is considerably slanted as it moves inside the channel, so that with increasing distance from the channel opening, the duration of flood becomes shorter than during the ebb tide. The lower, deeper areas near the opening of the channel are characterized by strong estuarine influence, with higher current velocity and stronger tides, while the estuarine water inflow is substantially reduced in the upper shallow areas. In addition, the upper part of the channel receives a continuous freshwater supply, especially during monsoons, through a small system of tidal creeks and streams.

2.2. Sample Collection and Analysis

Sediment samples were collected during April 2015 from Chairman Ghat (22◦30048.387600 N, 91◦506.607800 E, Noakhali, Chittagong division), using a hand-held corer with a depth penetration of 10 cm (Figure1). The collected samples were washed through a 0.5 mm mesh hand sieve, and polychaetes retained on the sieve were placed into plastic vials and ﬁxed with 5% formalin in the ﬁeld. After 2 days, the samples were washed with freshwater and transferred to 70% ethyl alcohol for further examination [17]. Diversity 2020, 12, 213 3 of 15

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Figure 1. Map showing the collection area (A). Source: [17]. Figure 1. Map showing the collection area (A). Source: [17]. Material was examined using stereo (Motic 6.5x–50X Zoom Stereo) and compound (Carl Zeiss, Material was examined using stereo (Motic 6.5x–50X Zoom Stereo) and compound (Carl Zeiss, Oberkochen, Germany) microscopes. Scanning electron microscope (SEM) observations were made Oberkochen, Germany) microscopes. Scanning electron microscope (SEM) observations were made with a Zeiss EVO LS15 SEM with a Robinson Backscatter Detector after critical-point drying and withcoating a Zeiss with EVO 20 nm LS15 gold SEM at the with Australian a Robinson Museum Backscatter [17]. Specimens Detector were after photographed critical-point using dryinga light and coatingmicroscope with 20 (Leica nm gold MZ16, at theLeica Australian Microsystems, Museum Wetzlar, [17]. Germany Specimens ) and were Spot photographed flex 15.2 (Leica using a lightMicrosystems, microscope (LeicaWetzlar, MZ16, Germany Leica ) with Microsystems, a camera attached. Wetzlar, In some Germany cases, the ) and material Spot was ﬂex stained 15.2 (Leica Microsystems,with methylene Wetzlar, blue to Germany increase )the with resolution a camera of diagnostic attached. characters. In some cases, All material the material examined was was stained withdeposited methylene at the blue Au tostralian increase Museum, the resolution Sydney (AM). of diagnostic characters. All material examined was deposited at the Australian Museum, Sydney (AM). 3. Results 3. Results 3.1. Systematics 3.1. SystematicsThe family of the studied species is Glyceridae Grube, 1850 [22]. The genus is Glycera Lamarck, 1818 [15], and the species is Glycera sheikhmujibi n. sp. The family of the studied species is Glyceridae Grube, 1850 [22]. The genus is Glycera Lamarck, (http://zoobank.org/urn:lsid:zoobank.org:pub:C2CEE260-5B4E-43B7-9251-2A0AB37EAB59). 1818 [15], and the species is Glycera sheikhmujibi n. sp. 3.2.(http: Material//zoobank.org Examined /urn:lsid:zoobank.org:pub:C2CEE260-5B4E-43B7-9251-2A0AB37EAB59).

3.2. MaterialThe Examinedholotype was AM W.48048, Bangladesh, Chairman Ghat, Noakhali, 22°30’48.3876’’ N, 91°5’6.6078’’ E; mid-intertidal zone of the saltmarsh, a tributary of Meghna Estuary; collected by Hossain,The holotype M.B, 3 April was 2015. AM The W.48048, paratypes Bangladesh, were AM W.48049, Chairman and AM Ghat, W.49884 Noakhali, (MI1726 22 and◦30 MI1727),048.3876 00 N, 91◦50as6.6078 well as00 E;AMW.49885 mid-intertidal (MI1728 zone and ofMI1729) the saltmarsh, mounted for a SEM. tributary of Meghna Estuary; collected by Hossain, M.B, 3 April 2015. The paratypes were AM W.48049, and AM W.49884 (MI1726 and MI1727), as well as AMW.49885 (MI1728 and MI1729) mounted for SEM. Diversity 2020, 12, 213 4 of 15

3.3. Generic Identification This species has been placed into the genus Glycera based on its overall morphological similarities with other species of Glycera, including the presence of different types of dense papillae on their proboscis. The genus Glycera Lamarck, 1818 [15] can easily be identified from other genera by the following unique characters [2,15]: acutely pointed, usually ringed prostomium with four terminal tentacles; and a long, eversible, club-like proboscis, provided with four hooked horny jaws and accessory lateral ailerons. The ailerons possess a more complicated structure with outer and inner rami, and sometimes an interramal plate. Parapodia have two anterior lobes with cirri and one or two posterior lobes, as well as the ventral chaetae compound and dorsal capillary chaetae.

3.4. Diagnosis The salient features of the new species are (i) the presence of three types of proboscideal papillae—type 1 papillae (main type), which are conical with three transverse ridges; type 2 papillae, which are conical with straight, median, longitudinal ridges; and type 3 papillae, which are round, shorter, and broader, with straight, median, longitudinal ridges; (ii) Y-shaped ailerons with gently incised triangular bases; and (iii) digitiform noto- and neuropodial lobes of almost equal size in the mid-body and long ventral cirri at the posterior end.

3.5. Description

3.5.1. Holotype The holotype has an incomplete, cylindrical body, which is elongated and tapered at both ends (Figure2A,B). The body reaches up to 42 mm long, with up to 158 segments, and has a width of 2.2 mm in the middle part of the body; preserved specimens in alcohol are whitish with numerous scattered small black pigmented spots (Figure2C,D). The body segment is biannulate (Figure2E), and the anterior annulus slightly shorter than posterior annulus. The prostomium is conical, pointed, and distinctly separated into about ten rings; the terminal ring has four antennae, and no nuchal organs or eyes (Figure2A,B and Figure3A,C). The parapodia of the ﬁrst two segments are uniramous, with a prechaetal and a postchaetal lobe, while the subsequent parapodia are biramous (Figures2B and3D). There are two unequal, triangular to digitiform, prechaetal and postchaetal anterior lobes, and lobes of similar length in mid-body (Figure2C, Figure3D, and Figure4A,D). Knob-like dorsal cirri from the second parapodium are inserted most clearly at the base of the anterior parapodia, as well as on the body wall far above parapodial base in the mid-body, and again near the posterior base (Figure2D–F). Ventral cirri are not distinct in the anterior part, but are well-developed in the posterior part (Figure4F). Retractile branchiae are present at chaetigers 27–31. Notochaetae slender capillaries with one margin covered with spines or hairs (Figure4A,C). There are neurochaetae homogomph spinigers (based on SEM) (Figure4B), as well as a pygidium with a terminal pair of slender, elongated cirri (Figure3G). The proboscis is very long, equal to 28 segments, bell-shaped, and densely covered with papillae, which are arranged in distinct longitudinal rows (Figures2A and3A,B). The papillae consist of three types: (1) numerous, conical papillae with three “V”- shaped ridges on posterior surface from top to bottom (Figure5C,D); (2) a few long, conical papillae, with one straight, median longitudinal ridge (Figure5C,D); and (3) very few, slightly shorter and broader, rounded papillae with a single very distinct median longitudinal ridge (Figure5C,D). Among the three types, type 2 is the longest. All papillae have small ciliated pores (Figure5D) and are smooth anteriorly. The terminal part of proboscis has four black hook-shaped jaws and accessory “Y”- shaped ailerons with gently incised triangular bases (Figure3B). Diversity 2020, 12, 213 5 of 15 Diversity 2020, 12, x FOR PEER REVIEW 5 of 14 Diversity 2020, 12, x FOR PEER REVIEW 5 of 14

Figure 2. Glycera sheikhmujibi n. sp.: (A) anterior dorsal view, (B) anterior lateral view, (C) lateral view FigureFigure 2. 2.Glycera Glycera sheikhmujibi sheikhmujibi n.n. sp.: sp.: (A (A) anterior) anterior dorsal dorsal view, view, (B) anterior (B) anterior lateral lateral view, view,(C) lateral (C) lateralview of anterior chaetigers, (D) mid-body chaetigers, (E) lower mid-body chaetigers, (F) posterior viewof ofanterior anterior chaetigers, chaetigers, (D ()D mid-body) mid-body chaetigers, chaetigers, (E ()E )lower lower mid-body mid-body chaetigers, chaetigers, (F ()F )posterior posterior chaetigers. j; jaw, a: antenna, p: proboscis, pr: prostomium, dc: dorsal cirri, nol = notopodial lobe, nel chaetigers.chaetigers. j; jaw,j; jaw, a: a: antenna, antenna, p:p: proboscis,proboscis, pr: pr: prostomium, prostomium, dc: dc: dorsal dorsal cirri, cirri, nol nol= notopodial= notopodial lobe, lobe,nel = neuropodial lobe; scale bars: 0.1 mm. nel == neuropodialneuropodial lobe; lobe; scale scale bars: bars: 0.1 0.1 mm. mm.

Figure 3. Glycera sheikhmujibi n. sp. scanning electron microscope (SEM) images of the (A) anterior Figure 3. Glycera sheikhmujibi n. sp. scanning electron microscope (SEM) images of the (A) anterior Figurelateral 3. view,Glycera (B) sheikhmujibiterminal ringn. of sp.the scanningjaws, (C) enlarged electron view microscope of prostomium, (SEM) images (D) anterior of the chaetigers, (A) anterior lateral view, (B) terminal ring of the jaws, (C) enlarged view of prostomium, (D) anterior chaetigers, lateral(E) mid-body view, (B) chaetigers, terminal ring (F) lower of the mid-body jaws, (C) enlargedchaetigers, view and of(G) prostomium, posterior chaetigers. (D) anterior ai: aileron, chaetigers, j: (E) mid-body chaetigers, (F) lower mid-body chaetigers, and (G) posterior chaetigers. ai: aileron, j: (E)jaw, mid-body a: antenna, chaetigers, vc: ventral (F )ciri, lower nol= mid-body notopodial chaetigers, lobe, nel= neuropodial and (G) posterior lobe, ac: chaetigers. annul ciri; scale ai: aileron, bars: j: jaw, a: antenna, vc: ventral ciri, nol= notopodial lobe, nel= neuropodial lobe, ac: annul ciri; scale bars: jaw,A a:and antenna, B = 200 µm, vc: ventralC and D= ciri, 100 nol µm,= notopodial E = 20 µm, lobe,F = 10 nel µm,= neuropodialG = 20 µm. lobe, ac: annul ciri; scale bars: A and B = 200 µm, C and D= 100 µm, E = 20 µm, F = 10 µm, G = 20 µm. A and B = 200 µm, C and D= 100 µm, E = 20 µm, F = 10 µm, G = 20 µm. Diversity 2020, 12, 213 6 of 15 DiversityDiversity 20202020,, 1212,, xx FORFOR PEERPEER REVIEWREVIEW 66 ofof 1414

FigureFigure 4. 4. GlyceraGlyceraGlycera sheikhmujibisheikhmujibi n.n. sp.sp. sp. SEMSEM SEM imagesimages images ofof of thethe the (( (AAA))) anterioranterior anterior parapodium,parapodium, parapodium, (( (BB))) compoundcompound neurochatae,neurochatae, (( (CCC))) capillarycapillary capillary notochaetae,notochaetae, notochaetae, (( (DDD))) mid-bodymid-body mid-body parapodia,parapodia, parapodia, (( (EEE))) posteriorposterior posterior parapodium,parapodium, parapodium, andand and (( (FFF))) posteriorposterior endend parapodia. parapodia. h:h: h: homogomphhomogomph homogomph spinigers,spinigers, spinigers, nol:nol: nol: notopodialnotopodial notopodial lobe,lobe, lobe, nene nel:l:l: neuropodialneuropodial neuropodial lobe,lobe, lobe, s:s: s: spines,spines,spines, vc:vc: ventralventral ventral ciri.ciri. ciri. ScaleScale Scale bars:bars: bars: A,A, A, B,B, B, C,C, C, andand and EE E === 101010 µm;µm;µm; DD D == = 202020 µm;µm;µm; FF F== =303030 µm.µm.µm.

FigureFigure 5. 5. GlyceraGlyceraGlycera sheikhmujibisheikhmujibi sheikhmujibi n.n.n. sp.sp. sp. SEMSEM SEM imagesimages images ofof of thethe the ((AA (A)) )proboscis;proboscis; proboscis; ((BB (B)) )enlargedenlarged enlarged viewview view ofof of thethe the proboscidealproboscideal papillae;papillae; (( CC)) posteriorposterior sideside side viewview view ofof of typetype type 1,1, 1, typetype type 2,2, 2, andand and typetype type 33 3 papillae;papillae; papillae; andand and (( (DD))) enlargedenlarged enlarged viewview ofof of typetype type 1and1and 1and typetype type 22 2 papillae.papillae. papillae. cp:cp: cp: ciliatedciliated ciliated porepore pore,,, pa:pa: pa: papillae,papillae, papillae, r:r: ridge.ridge. r: ridge. ScaleScale Scale bars:bars: bars: AA == 100A100= µm,µm,100 µBBm == , 2020B = µm,µm,20 µCCm, == 1010 C =µm,µm,10 andµandm, D andD == 22 D µm.µm.= 2 µm.

3.5.2.3.5.2. EtymologyEtymology Diversity 2020, 12, 213 7 of 15

3.5.2. Etymology The new species Glycera sheikhmujibi n. sp. was named in memory of Bangabandhu Sheikh Mujibur Rahman (shortened as Sheikh Mujib; 1920–1975), founder of Bangladesh. Sheikh Mujib was president (in absentia from 17 April 1971 to 12 January 1972), prime minister (12 January 1972 to 24 January 1975), and then president again of Bangladesh (25 January 1975 to 15 August 1975) in the early to mid-70s of the last century. He made an undeniable and significant contribution to the emergence of independent Bangladesh. He inspired the people of East Pakistan to stand up against the oppression of the Pakistani ruler and fight for the independence of the country with his solid, dedicated, and visionary leadership. After independence, he realized that the growth and prosperity of the country would have not been possible without proper research in different fields of science, and hence he established many research organizations, including BARC (Bangladesh Agricultural Research Council) and BCSIR (Bangladesh Council of Scientific and Industrial Research). While he was in power, he invested his wholehearted efforts building a "Sonar Bangla" to ensure peace and prosperity for all. Unfortunately, he was assassinated, along with most of his family members, on 15 of August 1975 by a group of disgruntled army officials. This year (17 March 2020 to 17 March 2021), Bangladesh is celebrating the “Mujib Year”, on the occasion of the 100th birth anniversary of Sheikh Mujibur Rahman. The United Nations Educational, Scientific and Cultural Organisation (UNESCO) has also decided to jointly celebrate the “Mujib Year” with Bangladesh at its 40th General Assembly.

3.6. Distribution, Ecology, and Habitat Glycera sheikhmujibi n. sp. is one of 11 species in the genus Glycera distributed in the Bay of Bengal region, and is the second species from Bangladeshi coastal waters. Currently, it is only known from the type locality on the central coast of Bangladesh; however, increased sample collection from other parts of the coastline might extend its distribution range. Sympatric species include Nephtys bangladeshi, Lumbrineris spp., Capitella spp., Goniada spp., Nereis spp., Magelona spp., and Naidadae, as well as the crustacean groups Ocypodidae, Palaemonidae, Gammaridae, and Harpecticoida. The species was collected from the muddy saltmarsh zone (intertidal zone), with a water depth range of 0.5 to 1.0 m during high tide. The zone is densely covered with the grass Spartina spp. and connected to the Meghna River Estuary, which falls to the Bay of Bengal near Hatiya and Swandwip islands. The average salinity, dissolved oxygen, pH, alkalinity, and temperature was 6 ppt, 9.15 ppm, 7.72, 180 ppm, and 29 ◦C, respectively.

4. Discussion The main diagnostic characteristics for the identification of glycerid species include shape and number of pre- and post-chaetal lobes, presence or absence of branchiae, shape of the aileron, and the structure of proboscidial papillae [2]. However, Fiege and Böggemann [23] and Rizzo et al. [1] found that parapodial lobes and branchiae are not reliable characters, because branchiae are retractable in some species, and the shape (size) and number of pre- and post-chaetal lobes are difficult to evaluate for some species. Therefore, they suggested the proboscidial papillae and ailerons to be the most reliable characters for the identification of species of Glycera. Glycera sheikhmujibi n. sp. can easily be distinguished from all other species of Glycera by the presence of three distinct types and shapes of proboscidial papillae (Table1). Diversity 2020, 12, 213 8 of 15

Table 1. List of Glycera recorded from near the Bay of Bengal Region, with their comparative characteristics, as per World Register of Maine Species, WoRMS [24].

Body Length, Width (Max) in Prostomium Shape, No. Proboscis Arrangement, and Species Type Locality Data Source mm, No. of Chaetigers Body Pigmentation of Rings, and No. of Type and Shape of Papillae (Holotype/Neotype) Prostomium Antenna Two types of papillae; type Indonesia, 1—numerous, digitiform, Glycera brevicirris 13 mm, 2 mm for 44 chaetigers Philippines, Indian Based on Rizzo et al. [1] Yellowish Conical with 10 rings anteriorly smooth; and type Grube, 1870 [14] (syntype) Ocean 2—isolated, broader with longitudinal ridge G. cinnamomea 94 mm, 3 mm at 75 chaetiger, Sri Lanka, India Based on original description White Conical with 11 rings Papillae short and digitiform Grube, 1874 [25] 195 chaetigers (holotype) G. embranchiata India Nomen dubium -- Krishnamoorthi, 1962 [26] G. lancadivae Reversed cone, Sri Lanka Based on original description 50 mm, 3mm, 158 (holotype) Yellowish-brown Hair-like papillae Schmarda, 1861 [13] below the jaws. 16 larger Acutely conical, with G. manorae Manora Shoal, Small, cylindrical, unguiculate Based on original description 70 mm, 5 mm, n/a (holotype) n/a 10–12 rings and four Fauvel, 1932 [27] Karachi, India papillae tentacles Two kinds of papillae: G. posterobranchia Marinduque Island, n/a, equal in length to Original 75 mm, 3 mm, 90 (holotype) Light brown sucker-like and large blunt Hoagland, 1920 [28] Philippines ﬁrst eight chaetigers conical G. rutilans Sri Lanka Nomen nudum Grube in McIntosh, 1885 [29] Two types of papillae: short, G. sagittariae Oﬀ Arrou Island, globular or ovate; and long and Based on original description 110, 5, n/a Not availavle (n/a) n/a McIntosh, 1885 [29] Madras coast, India slender without terminal nail- like appendage. G. subaenea 52 mm, 2.2 mm for 166 Philippines Based on original description n/a n/a n/a Grube, 1878 [30] (holotype) segments G. tesselata Prostomium with 16–17 India Based on original description 48 mm, 6 mm, incomplete n/a n/a Grube, 1863 [31] rings Three types of papillae: type 1—numerous, digitiform with 42 mm and 2.2 mm for 158 Whitish with black Conical prostomium with 2–3 ridges; type 2—isolated Glycera sheikhmujibi n. sp. Noakhali, Bangladesh Based on present study segments numerous black spot 10–11 rings with one median straight ridge; and type 3—broader with a longitudinal ridge Diversity 2020, 12, 213 9 of 15

Table 1. Cont.

Body Length, Width (Max) in Prostomium Shape, No. Proboscis Arrangement, and Species Type Locality Data Source mm, No. of Chaetigers Body Pigmentation of Rings, and No. of Type and Shape of Papillae (Holotype/Neotype) Prostomium Antenna Noto- & neuropodia; anteriror Jaws and Aileron Branchiae Chaetae Remarks and posterior chaetigers Anterior parapodia uniramous Parapodia with 2–4 with a pre- and postchaetal Aileron is triangular, simple capillary Glycera brevicirris lobe where dorsal cirrus absent; with an elongated Absent notochaetae and 5–13 Grube, 1870 [14] posterior parapodia biramous process on one side spinigerous with two triangular to neurochaetae digitiform prechaetal lobes G. cinnamomea n/a n/a Grube, 1874 [25] G. embranchiata Böggemann [2] reported Nomen dubium Krishnamoorthi, 1962 [26] as a nomen nudum Parapodia biramous and tongue-like, but in the anterior Jaws with large tooth Few chaetae—curved G. lancadivae segments cylindrical; dull, Branchiae absent in posterior and have a bent and capillary, and Schmarda, 1861 [13] cone-shaped ventral cirrus in segments process partly spinigers the first segments, pointed cone in the posterior segments Parapodia with two sharp, Dorsal capillary Jaws obliquely triangular, equal anterior lobes chaetae with narrow truncated, aileron is and two similar but shorter wings; ventral chaetae G. manorae Retractile branchiae beginning triangular with an blunt posterior lobes; dorsal compound Fauvel, 1932 [27] at about the 17th foot elongated process on cirrus elongated, knob near homogomph with one side base of parapodia and ventral finely serrated cirrus triangular terminal piece. Anterior parapodia with long, Two kinds: simple conical dorsal lobes; posterior dorsal capillaries with parapodia elongated, divided Branchiae begins at 25th G. posterobranchia Jaws with lateral finely serrated edges into one dorsal and two ventral chaetiger as small knobs at the Hoagland, 1920 [28] appendages and ventral rami; dorsal cirrus a rounded dorsal base of parapodia compounds with tubercle and ventral cirrus finely serrated blade similar shape to dorsal lobe G. rutilans Böggemann [2] reported Nomen nudum Grube in McIntosh, 1885 [29] as a nomen nudum Diversity 2020, 12, 213 10 of 15

Table 1. Cont.

Body Length, Width (Max) in Prostomium Shape, No. Proboscis Arrangement, and Species Type Locality Data Source mm, No. of Chaetigers Body Pigmentation of Rings, and No. of Type and Shape of Papillae (Holotype/Neotype) Prostomium Antenna Parapodia with two equal elongated, tapering anterior G. sagittariae Aileron with two long lobes, and two equal, blunt, Present, simple and short n/a Fauvel, 1932 [27] dagger-like processes triangular posterior lobes; beginning at 40th segment dorsal cirrus more or less remote Posterior parapodial lobes Branchiae present and longer than the anterior ones; positioned at the anterior wall G. subaenea lower lobes triangular and n/a of parapodium, separated into n/a Grube, 1878 [30] wider than the upper ones, 2–3 ﬁngerlike ﬁlaments, longer anterior lobes equally long, than ventral cirrus rounded G. tesselata n/a n/a n/a n/a Grube, 1863 [31] Parapodia with digitiform Dark, hook-shaped prechaetal and postchaetal Branchiae present, retractile, jaws and ailerons lobes; knob-like dorsal cirrus 5–6 slender capillary Glycera sheikhmujibi n.sp. commencing from the 27th to with gently incised along the body and long notochaetae 31st segments bases ventral cirrus present posteriorly Diversity 2020, 12, 213 11 of 15

Glycera sheikhmujibi n. sp. shares no diagnostic characteristics with either Glycera lancadivae, the only known species from Bangladesh [12], or fragments of another glycerid described by Muir and Hossain [16]; however, it clearly differs in many other aspects, especially in the form of three distinct types of proboscidial papillae. Again, Böggemann [2] mentioned that G. lancadivae is a nomen dubium, and it is almost similar to G. brevicirris. Glycera sheikhmujibi n. sp. seems to resemble Glycera nicobarica Grube, 1867 [32] and Glycera macintoshi Grube, 1877 [33] in the shape of ailerons, parapodial lobes, and types and shapes of the proboscidial papillae (Table1). However, G. nicobarica and G. macintoshi have only two different types of papillae: G. nicobarica possesses few ovate papillae without ridges, and numerous leaf-like ones with five to six “U”-shaped ridges, and G. macintoshi has conical proboscidial papillae with three transverse ridges. Recently, G. nicobarica has been synonymized with Glycera unicornis Lamarck, 1818 by Read [24]. It has been argued that the proboscidial papillae may vary due to preservation, sample preparation, and development of papillae; however, for the sample collection and preservation of G. sheikhmujibi n. sp., standard procedures were followed. In addition, G. sheikhmujibi n. sp. differs from G. macintoshi by the presence of two equal triangular pre- and postchaetal lobes, whereas shorter, rounded neuropodial postchaetal lobes are present in G. macintoshi. Glycera. embranchiata Krishnamoorthi, 1962 [26] (known from India) is a nomen dubium, as there is no description of the species in the original report, and G. rutilans Grube, 1877 [33] (known from Sri Lanka) is nomen nudum, as reported in Böggemann [2]. Glycera convoluta, G. longipinnis, G. rouxii, and Glycinde oligodon, all reported from the Bay of Bengal region, have not been accepted by Böggemann [2], as G. convoluta is a junior synonym of G. tridactyla, G. longipinnis is a junior synonym of G. sphyrabrancha, G. rouxii is a junior synonym of G. unicornis, and Glycinde oligodon belongs to the family Goniadidae. Although Glycera tesselata Grube, 1863 [31] is a good species and is accepted by Böggemann [2] and Read [24], it is poorly described in the original description. The first procedure in any ecological work or applied research with organisms is an exercise in taxonomy. Taxonomy provides the fundamental understanding about the components of biodiversity, which is badly needed for effective decision-making regarding conservation, management, and sustainable use of the studied organisms. In addition, the loss of biodiversity due to human activities and climate change should be of major concern to everyone, because it threatens the functioning of an ecosystem. Despite this, there is very little information on the taxonomy of polychaetes from Bangladeshi coastal waters compared with those of neighbouring countries. To date, only thirty species have been identified from Bangladesh, which is a very low number compared to known polychaete species (~10,000) in the world. With a diverse coastline of about 720 km, it is hoped that the number of polychaete species will be increased with further studies. Key to the species of genus Glycera from the Bay of Bengal region (modified from Muir and Hossain [15]) is as follows:

1. Proboscideal papillae do not have a terminal ﬁngernail structure 2 – Proboscideal papillae have a terminal ﬁngernail structure 6 2. There is one postchaetal lobe in all parapodia 3 – There are two postchaetal lobes (at least) on the mid-body parapodia 5 3. Mid-body, the notopodial prechaetal lobes are shorter than the neuropodial lobes, and branchiae are absent Glycera lapidum Quatrefages, 1866 [24]. – Mid-body, the prechaetal lobes are about same length or longer than the notopodial lobes. Branchiae are present or absent 4 Diversity 2020, 12, 213 12 of 15

4. The proboscideal papillae are digitiform and without ridges, ailerons have deeply incised bases, and simple digitiform branchiae are situated termino-dorsally on the parapodia Glycera sphyrabrancha Schmarda, 1861 [12]. – Conical proboscideal papillae with 5–20 transverse ridges, ailerons have slightly arched bases, and branchiae are absent Glycera oxycephala Ehlers, 1887 [25].

5. Ailerons have gently incised bases; long, mid-body postchaetal lobes are digitiform and of about equal length; three types of proboscideal papillae, with the main type having fewer than three ridges; and branchiae are absent Glycera sheikhmujibi n. sp. – Ailerons have an interamal plate and triangular bases; mid-body parapodia have slender, triangular, notopodial and distinctly shorter, rounded neuropodial postchaetal lobes. The retractile branchiae are situated medially on anterior side of parapodia 7 6. Digitiform proboscideal papillae have a straight, median, longitudinal ridge Glycera tesselata Grube, 1863 [26]. – Digitiform proboscideal papillae have 6–20 transverse ridges Glycera brevicirris Grube, 1870 [13]. 7. Parapodia have slender, triangular, notopodial and distinctly shorter, rounded, neuropodial postchaetal lobes; and branchiae are simple, digitiform, and retractile Glycera nicobarica Grube, 1867 [18]. – Parapodia have two slender, triangular postchaetal lobes of about the same length, or notopodial lobes that are only slightly longer than the neuropodial lobes; branchiae are digitiform and retractile with 1–2 rami Glycera unicornis Lamarck, 1818 [14]. 8. The mid-body parapodia have two slender. triangular postchaetal lobes of about the same length 9 – The mid-body parapodia have slender, triangular notopodial and shorter, more or less rounded, neuropodial postchaetal lobes 10 9. Parapodia do not have branchiae Glycera onomichiensis Izuka, 1912 [27]. – There are 1–5 digitiform branchial rami situated dorsally on the parapodial bases Glycera cinnamomea Grube, 1874 [19]. 10. In mid-body and posterior parapodia, the neuropodial postchaetal lobes are more or less rounded. Simple digitiform branchiae are situated termino-dorsally on the parapodia 11 – In the posterior parapodia are neuropodial postchaetal lobes as long as the notopodial lobes, and equally slender and triangular. Simple digitiform branchiae are situated medio-dorsally on the parapod

Glycera posterobranchia Hoagland, 1920 [28]. 11. All biramous parapodia have two postchaetal lobes. Proboscideal papillae have long, medium, or short stalks. 12 Diversity 2020, 12, 213 13 of 15

– In the anterior parapodia, there is only one, medially inserted, slender triangular postchaetal lobe. The proboscideal papillae have short stalks Glycera macrobranchia Moore, 1911 [29]. 12. Proboscideal papillae have long stalks 13 – Proboscideal papillae have medium-length or short stalks 14 13. There are stalk without ridges and ailerons with pointed triangular bases Glycera alba Müller, 1776 [30]. – There are stalks with numerous ridges and ailerons with triangular bases Glycera natalensis Day, 1967 [31]. 14. The proboscideal papillae have short stalks, the prostomium consists of about 11–15 rings, and ailerons have triangular bases Glycera tridactyla Schmarda, 1861 [12]. – The proboscideal papillae have medium-length stalks, the prostomium consists of about 19–28 rings, and ailerons have pointed triangular bases Glycera africana Arwidsson, 1899 [32].

Author Contributions: Conceptualization: M.B.H.; methodology: M.B.H.; formal analysis: M.B.H.; investigation: M.B.H.; writing—original draft preparation: M.B.H.; writing—review and editing: P.H.; visualization: P.H.; resources: P.H.; supervision: P.H. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Acknowledgments: Thanks are due to AMRI (Australian Museum Research Institute) for providing lab space, facilities, and access to the library. We would like to thank Sue Lindsay, who helped greatly with the SEM photographs. Field and lab assistance was provided by some students, namely Amir, Jewel, Tanmay, and Rasel, and the Milonof Fisheries and Marine Science Department are acknowledged. Conﬂicts of Interest: The authors have no conﬂict of interest.

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